Workprint – March 2019

One of my “defining traits” is a quite frankly ridiculous lack of organisational skills, in fact it comes as something of a surprise to people who’ve known me for any length of time that I get blog posts up on what are, by my standards, a fairly regular basis. As a result of that there are a lot of projects hanging around my hard disks which have been put aside for one reason or another, sometimes either on the cusp of being completed or actually done and dusted (although in one case it’s a port and in need of an overhaul since the original version has subsequently been improved).

So with spring approaching I plan to apply the defibrillator a few and right now I have two in mind, both of which C64CD projects; I’m keeping one close to my chest until it starts to properly exist past a few sprite routines that need recoding anyway, but the other is a reworking of Stercore 64 which re-imagines it as a bespoke C64 game rather than a Spectrum port. That’s more difficult than it might sound because the game scrolls at a character per frame and the landscape has two layers with one passing over the sprites, so my “plan” is to rely on the way that one of the character multicolours always remains behind the sprites regardless of the priority register.

That’ll give me a black background with one other colour for the background layer and, if I can scroll the colour RAM, five or six foreground colours; the sprites can then pass between the two without needing any complicated sprite clipping code since the hardware will do the work for me. That said, actually drawing something half decent with those restrictions is difficult and, whilst games like Implosion and Shadow Skimmer carry it off well, I’m no John Cassells or Mat Sneap…

Watching Little Demos (Atari ST)

“Robb says wow!” We’re going back to the early releases of Atari ST legends The Exceptions for a quick squint at the two demos which followed on and indeed evolved from Readme.prg – this would all lead to The B.I.G. Demo in early 1988 but that’s probably a post for another time (along with quite a bit of recording since the name isn’t exactly ironic).

The first of these two releases is Little Sound Demo and the large scrolling message with palette rotation in the background returns for another outing, but this time the picture has some raster bars through the TEX logo instead of the background and some decorative palette rotation around the indicator saying which piece of music is currently playing. There are twelve tunes in total which are mostly conversions of Rob Hubbard’s work from the C64 – hence the picture of a Breadbin getting lamped in the back of its “head” by the music emitting from an ST – with a couple of pieces composed by new group member Mad Max who also did the conversions and wrote the music driver.

That handle might not be familiar to those outside the Atari ST scene, but a few folks might recognise his real name Jochen Hippel since he was the musician for several games including Wings Of Death and the ST versions of Turrican and Turrican 2. He also released an album mostly consisting of reworked versions of his game tunes called Give It A Try and I’ve got a copy of that CD knocking around… somewhere?

Little Color Demo continues where its predecessor left off in expanding on what Readme.prg did and wedging more colour and action into the display like the barrel scroller between the two pictures of Rob Hubbard, more palette rotation under the tune list and some serious colour splitting on the lower scroller. One feature that wasn’t carried over from the previous release however is Mad Max’s compositions, there’s only eight tunes in this demo and everything is a Hubbard cover apart from the version of Axel F.

It’s fascinating to see the code mutate and evolve as the coders learnt more about their machine of choice but, whilst the bespoke music driver and converted tunes are a major plus, the hyperbole around them is probably pushing things a little; the tunes are good if sometimes missing elements – or large chunks in the case of Flash Gordon and International Karate – but the sounds being used don’t really hold a candle to their C64 equivalents. Rob himself was already doing Atari ST tunes in 1987 including a reworked version of Human Race tune 4 for Goldrunner, which was coded by the well-known game developer Steve Bak who, by a sad coincidence, passed away a couple of days ago whilst this post was being written.

Looking at these two as a whole, as with Readme.prg they were a little underwhelming to the teenage version of me waiting for the Atari ST to really offer stunning graphics and sound – hearing those covers of older Rob Hubbard tunes was cool but nowhere near enough to entice anyone away from the C64 in that respect – but the early works from Mad Max did offer some promise for the future and both demos are significant milestones in the Atari ST’s scene history.

Releasing Level One (C64)

We’ve reached the end game for 2018’s Intro Creation Competition so there’s been an inrush of new releases over the last couple of days including one last contribution from yours truly with the ever patient Andy Vaisey on music. It went through a few names but Level One was the final choice simply because it looks somewhat like a game.

The scrolling area takes up the entire regular screen – 39 visible characters across by 25 down – and is being moved using a double buffered scroll routine similar to the ones employed by games which in turn leans on some Run-Length Encoded background data. It also uses the C64’s Extended Colour Mode so, although there are only 64 characters available in the font, it can have four possible background colours for each character so I don’t have to scroll the colour RAM.

Something a little trickier is happening in the black bands above and below the scrolling; these are ten pixels high and sat in the borders, but containing a seven character wide Cosine logo and nineteen characters of either static text or scrolling message. To get twenty six characters into that space the code has to abuse the ghostbyte, splitting it at five points on each scanline to produce the extra two characters (they’re at the far left and right of the screen on both lines) and mask off the raster bars for the areas between the sprites.

I suspect a few people will be asking themselves if a game with similar graphics would be possible and the answer is a sort-of-yes, although drawing decent backgrounds when restricted to just 64 characters is bloody tricky!